cn.edu.jnu.ie.backend.NutchDocument.java Source code

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Here is the source code for cn.edu.jnu.ie.backend.NutchDocument.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package cn.edu.jnu.ie.backend;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.VersionMismatchException;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableUtils;

/** A {@link NutchDocument} is the unit of indexing.*/
public class NutchDocument implements Writable, Iterable<Entry<String, NutchField>> {

    public static final byte VERSION = 2;

    private Map<String, NutchField> fields;

    private float weight;

    public NutchDocument() {
        fields = new HashMap<String, NutchField>();
        weight = 1.0f;
    }

    public void add(String name, Object value) {
        NutchField field = fields.get(name);
        if (field == null) {
            field = new NutchField(value);
            fields.put(name, field);
        } else {
            field.add(value);
        }
    }

    public Object getFieldValue(String name) {
        NutchField field = fields.get(name);
        if (field == null) {
            return null;
        }
        if (field.getValues().size() == 0) {
            return null;
        }
        return field.getValues().get(0);
    }

    public NutchField getField(String name) {
        return fields.get(name);
    }

    public NutchField removeField(String name) {
        return fields.remove(name);
    }

    public Collection<String> getFieldNames() {
        return fields.keySet();
    }

    /** Iterate over all fields. */
    public Iterator<Entry<String, NutchField>> iterator() {
        return fields.entrySet().iterator();
    }

    public float getWeight() {
        return weight;
    }

    public void setWeight(float weight) {
        this.weight = weight;
    }

    public void readFields(DataInput in) throws IOException {
        fields.clear();
        byte version = in.readByte();
        if (version != VERSION) {
            throw new VersionMismatchException(VERSION, version);
        }
        int size = WritableUtils.readVInt(in);
        for (int i = 0; i < size; i++) {
            String name = Text.readString(in);
            NutchField field = new NutchField();
            field.readFields(in);
            fields.put(name, field);
        }
        weight = in.readFloat();
    }

    public void write(DataOutput out) throws IOException {
        out.writeByte(VERSION);
        WritableUtils.writeVInt(out, fields.size());
        for (Map.Entry<String, NutchField> entry : fields.entrySet()) {
            Text.writeString(out, entry.getKey());
            NutchField field = entry.getValue();
            field.write(out);
        }
        out.writeFloat(weight);
    }

    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("doc {\n");
        for (Map.Entry<String, NutchField> entry : fields.entrySet()) {
            sb.append("\t");
            sb.append(entry.getKey());
            sb.append(":\t");
            sb.append(entry.getValue());
            sb.append("\n");
        }
        sb.append("}\n");
        return sb.toString();
    }
}